package dome3;


public class SingleLinkedList {
    static class ListNode {
        public int val;
        public ListNode next;

        public ListNode(int val) {
            this.val = val;
        }
    }
    public ListNode head;
    public void addFirst(int data) {
        ListNode list = new ListNode(data);
        list.next = head;
        head = list;
    }
    //尾插法
    public void addLast(int data) {
        ListNode list = new ListNode(data);
        if(head == null) {
            head = list;
            return;
        }
        ListNode cur = head;
        while(cur.next!=null) {
            cur = cur.next;
        }
        cur.next = list;
    }
    //任意位置插入,第一个数据节点为0号下标
    public boolean addIndex(int index,int data) {
        if (index < 0 || index > size()) {
            return false;
        }
        ListNode list = new ListNode(data);
        if (index == 0) {
            addFirst(data);
            return true;
        }
        if(index == size()) {
            addLast(data);
            return true;
        }
        ListNode cur = findIndex(index);
        list.next = cur.next;
        cur.next = list;
        return true;
    }
    private ListNode findIndex(int index) {
        int count = 0;
        ListNode cur = head;
        while(count!=index-1) {
            cur = cur.next;
            count++;
        }
        return cur;
    }
    //查找是否包含关键字key是否在单链表当中
    public boolean contains(int key) {
        ListNode cur = head;
        while(cur!=null) {
            if(cur.val==key) {
                return true;
            }
            cur = cur.next;
        }
        return false;
    }
    //删除第一次出现关键字为key的节点
    public void remove(int key) {
        if(head == null) {
            return;
        }
        if(head.val == key) {
            head = head.next;
            return;
        }
        ListNode list = fingKey(key);
        if(list == null) {
            return;
        }
        list.next = list.next.next;
    }
    private ListNode fingKey(int key) {
        ListNode cur = head;
        while(cur.next!=null) {
            if(cur.next.val==key) {
                return cur;
            }
            cur = cur.next;
        }
        return null;
    }
    //删除所有值为key的节点
    public void removeAllKey(int key) {
        if(head == null) {
            return;
        }
        ListNode cur = head;
        while(cur.next!=null) {
            if(cur.next.val == key) {
                cur.next = cur.next.next;
            }else {
                cur = cur.next;
            }
        }
        if(head.val == key) {
            head = head.next;
        }
    }
    //得到单链表的长度
    public int size() {
        int count = 0;
        ListNode cur = head;
        while(cur!=null) {
            cur = cur.next;
            count++;
        }
        return count;
    }
    public void display() {
        ListNode cur = head;
        while(cur!=null) {
            System.out.print(cur.val + " ");
            cur = cur.next;
        }
        System.out.println();
    }
    public void clear() {
        ListNode cur = head;
        while(cur!=null) {
            ListNode curN = cur.next;
            cur.next = null;
            cur = curN;
        }
        head = null;
    }
}
